Unequal Weighting in Numerical Taxonomy

Proctor, Jean R.; Kendrick, W. B.

doi:10.1038/197716a0

Cited by 18 publications

(6 citation statements)

References 4 publications

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“…where w k = weights for the kth character and |.....| is the absolute value operator. The weights for this city-block metric were defined as 1 q where q = 1 or the number of sub-character states scored underneath that character (if it had any)-following the philosophy of Proctor and Kendrick (1963) without the additional plus 1. These weighted 'band pass…”

Section: Discussionmentioning

confidence: 99%

The gut epithelium from feeding to fasting in the predatory soil mite Pergamasus longicornis (Mesostigmata: Parasitidae): one tissue, two roles

Bowman

2019

Exp Appl Acarol

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A review of acarine gut physiology based on published narratives dispersed over the historical international literature is given. Then, in an experimental study of the free-living predatory soil mite Pergamasus longicornis (Berlese), quantitative micro-anatomical changes in the gut epithelium are critically assessed from a temporal series of histological sections during and after feeding on larval dipteran prey. An argued functional synthesis based upon comparative kinetics is offered for verification in other mesostigmatids. Midand hind-gut epithelia cell types interconvert in a rational way dependent upon the physical consequences of ingestion, absorption and egestion. The fasted transitional pseudostratified epithelium rapidly becomes first squamous on prey ingestion (by stretching), then columnar during digestion before confirmed partial disintegration (gut 'lumenation') during egestion back to a pseudo-stratified state. Exponential processes within the mid-and endodermic hind-gut exhibit 'stiff' dynamics. Cells expand rapidly (t 1∕2 = 22.9-49.5 min) and vacuolate quickly (t 1∕2 = 1.1 h). Cells shrink very slowly (t 1∕2 = 4.9 days) and devacuolate gently (t 1∕2 = 1.0-1.7 days). Egestive cellular degeneration has an initial t 1∕2 = 7.7 h. Digestion appears to be triggered by maximum gut expansion-estimated at 10 min post start of feeding. Synchrony with changes in gut lumen contents suggests common changes in physiological function over time for the cells as a whole tightly-coupled epithelium. Distinct in architecture as a tissue over time the various constituent cell types appear functionally the same. Functional phases are: early fluid transportation (0-1 h) and extracellular activity (10-90 min); through rising food absorption (10 min to > 1 day); to slow intracellular meal processing and degenerative egestive waste material production (1 to > 12 days) much as in ticks. The same epithelium is both absorptive and degenerative in role. The switch in predominant physiology begins 4 h after the start of feeding. Two separate pulses of clavate cells appear to be a mechanism to facilitate transport by increasing epithelial surface area in contact with the lumen. Free-floating cells may augment early extracellular lumenal digestion. Possible evidence for salivary enzyme alkaline-related extra-corporeal digestion was found. Giant mycetome-like cells were found embedded in the mid-gut wall. Anteriorly, the mid-gut behaves like a temporally expendable food processing tissue and minor long-term resistive store. Posteriorly the mid-gut behaves like a major assimilative/ catabolic tissue and 'last-out' food depot (i.e., a 'hepatopancreas' function) allowing the mite to resist starvation for up to 3.5 weeks after a single meal. A 'conveyor-belt' wave Extended author information available on the last page of the article Research Council grant B/77307818 at Liverpool John Moores University. Thanks go to Susan Bjornson (then at University of Alberta, Canada) for advice on invertebrate sporozoans and Don E Johnston (Ohio Sta...

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Section: Discussionmentioning

confidence: 99%

The gut epithelium from feeding to fasting in the predatory soil mite Pergamasus longicornis (Mesostigmata: Parasitidae): one tissue, two roles

Bowman

2019

Exp Appl Acarol

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“…Possibly we need not be too concerned about this since experience has shown that even considerable weighting of characters does not affect the computation of similarity coefficients unduly, i.e., the similarity matrices are quite robust. For this reason weighting of characters as proposed by Proctor and Kendrick (1963) may not really be necessary.…”

Section: Objections To the Use Of Phenetic Methodsmentioning

confidence: 97%

The Two Taxonomies: Areas of Agreement and Conflict

Sokal¹,

Camin²

1965

Systematic Zoology

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“…However, in a recent stimulating review Johnson (1968) has drawn attention to a weighting paradox discussed in an unjustly-neglected paper by Kendrick (1965), and arising from earlier taxonometric studies by the same author (Proctor and Kendrick 1963;Kendrick and Proctor 1964); this concerns the not uncommon case of serially dependent attributes. A simple example would be: fruit a drupe, capsule or berry;…”

Section: Introductionmentioning

confidence: 99%

The Problem of Attribute‐weighting in Numerical Classification

Williams¹

1969

TAXON

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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. International Association for Plant Taxonomy (IAPT)is collaborating with JSTOR to digitize, preserve and extend access to Taxon. SummarySerially dependent attributes arise when a primary attribute controls a string of secondary attributes, so that the system takes the form (X or not-X; if X, then Y or not-Y, Z or not-Z; otherwise question inapplicable). Kendrick (1965) pointed out that in numerical classifications, unless steps are taken to apply differential weighting to primary and secondary attributes, the secondaries may over-ride the primaries, and that this may result in unacceptable classifications. His suggestions are re-examined in the light of modern metric and information-statistic programs; it is concluded that the suggestions are numerically sound, but require modification in the context of modem programs. Essentially, the revised suggestions consist in reducing the contribution of secondary attributes by dividing by the number of secondaries in the string, and then taking the number of secondaries as zero when consolidating into an overall similarity measure.

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Unequal Weighting in Numerical Taxonomy

Cited by 18 publications

References 4 publications

The gut epithelium from feeding to fasting in the predatory soil mite Pergamasus longicornis (Mesostigmata: Parasitidae): one tissue, two roles

The gut epithelium from feeding to fasting in the predatory soil mite Pergamasus longicornis (Mesostigmata: Parasitidae): one tissue, two roles

The Two Taxonomies: Areas of Agreement and Conflict

The Problem of Attribute‐weighting in Numerical Classification

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